What is the diagnosis for a patient who develops hypotension and low oxygen saturation (SpO2) shortly after blood transfusion?

Diagnosis: Transfusion-Related Acute Lung Injury (TRALI)

The most likely diagnosis is Transfusion-Related Acute Lung Injury (TRALI), given the acute onset of hypotension and severe hypoxemia (SpO2 88%) occurring within 15 minutes of blood transfusion. 1, 2

Clinical Reasoning

Why TRALI is the Answer (Option B)

• TRALI characteristically presents with non-cardiogenic pulmonary edema within 1-2 hours after transfusion, with key clinical features including hypoxemia, dyspnea, and hypotension 2
• The combination of hypotension AND hypoxemia (SpO2 88%) occurring within 15 minutes is pathognomonic for TRALI 1, 2
• The mechanism involves donor leukocyte antibodies (HLA class I, class II, or granulocyte-specific antibodies) interacting with recipient neutrophils, causing acute respiratory distress and cardiovascular instability 2
• TRALI is a leading cause of transfusion-related mortality despite being underdiagnosed and underreported 2

Why NOT Acute Hemolytic Transfusion Reaction (Option A)

• Acute hemolytic transfusion reaction typically presents with the clinical triad of pain at the IV site, difficulty breathing, and fever occurring within 10 minutes 3
• The question does not mention pain at the IV site or fever, which are hallmark features of hemolytic reactions 3
• While hemolytic reactions can cause hypotension, the prominent hypoxemia (SpO2 88%) points more toward a pulmonary process like TRALI rather than intravascular hemolysis 3
• Hemolytic reactions have a much lower incidence (1:70,000 per unit) compared to TRALI 3

Why NOT Allergic Reaction (Option C)

• Allergic reactions typically manifest with urticaria, pruritus, and skin flushing rather than the combination of hypotension and severe hypoxemia 3
• When allergic reactions cause respiratory symptoms, they are usually due to bronchospasm or laryngeal edema, not the acute dyspnea from systemic inflammation and pulmonary edema seen here 3
• The absence of mentioned skin findings (rash, hives, itching) makes allergic reaction less likely 3

Critical Management Steps

Immediate Actions (First 5 Minutes)

• Stop the transfusion immediately and maintain IV access with normal saline 2
• Administer 100% oxygen to address the severe hypoxemia 2
• Call for help and prepare for potential intubation and mechanical ventilation 2
• Monitor vital signs every 5-15 minutes 1

Hemodynamic Support

• Maintain adequate blood pressure with IV fluid resuscitation using normal saline or lactated Ringer's solution 2
• AVOID DIURETICS - this is a critical pitfall, as diuretics are ineffective and potentially harmful in TRALI (unlike TACO where they are indicated) 2
• Prepare vasopressors if fluid resuscitation is insufficient to maintain MAP >65-70 mmHg 1

Post-Stabilization

• Transfer to intensive care for continued monitoring and mechanical ventilation if needed 2
• Continue observation for at least 24 hours, as TRALI can evolve over the first 6-12 hours post-transfusion 2
• Report the reaction to the blood bank to remove the implicated donor from the pool 2

Key Clinical Pitfall

The most dangerous error is administering diuretics thinking this is TACO (circulatory overload). While both TACO and TRALI present with respiratory distress, TACO occurs with fluid overload signs (elevated JVP, peripheral edema, cardiovascular changes) and responds to diuretics, whereas TRALI is non-cardiogenic pulmonary edema requiring supportive care with oxygen, NOT volume removal 1, 2.